CARDIOVASCULAR MEDICINE

Impairment of cardiopulmonary receptor sensitivity in the early phase of heart failure

P A Modesti, G Polidori, I Bertolozzi, S Vanni, I Cecioni

Clinica Medica e Cardiologia, University of Florence, Florence, Italy

Correspondence to:
Correspondence to:
Professor Pietro A Modesti
Clinica Medica e Cardiologia, University of Florence, Viale Morgagni 85, 50134 Florence, Italy; pa.modesti{at}dfc.unifi.it

Objectives: To characterise the efficiency of the cardiopulmonary baroreflex system in the early phase of heart failure and its relation to limitation of physical activity.

Design: Forearm blood flow (venous occlusion plethysmography), vascular resistance, and central venous pressure (CVP), estimated from an antecubital vein, were measured in the supine position at baseline and 15 minutes after application of lower body negative pressure at -7 and -14 mm Hg (receptor downloading) or leg raising (receptor loading).

Subjects: Heart failure patients without limitation (NYHA class I; n = 18) or with slight limitation of physical activity (NYHA class II; n = 13), and 11 healthy controls.

Results: The efficiency of the cardiopulmonary baroreflex function, expressed by the slope of the relation between CVP changes and the corresponding changes of calculated forearm vascular resistance (gain), was reduced both in NYHA class I patients (mean (SD) -1.99 (0.83) v -2.78 (0.66) in controls; p < 0.05) and NYHA class II patients (-1.29 (0.5); p<0.001 v controls). However, change in peripheral vascular resistance during preload increase was similar in controls (-3.3 (0.9) units) and in NYHA class I patients (-3.3 (2.1) units; NS v controls), and was significantly reduced only in NYHA class II patients (-1.6 (1.3) units, p < 0.03 v controls). The gain in the cardiopulmonary reflex was related to the distance walked during the six minute corridor test.

Conclusions: A reduced tonic efficacy of the cardiopulmonary reflex system is already detectable in the early phase of heart failure, the impairment in acute response to preload increase being detectable only in symptomatic patients.

Keywords: heart failure; cardiopulmonary baroreceptors; lower body negative pressure; peripheral vascular tone

Abbreviations: ANP, atrial natriuretic peptide; AVP, arginine vasopressin, BNP, brain natriuretic peptide; CVP, central venous pressure; LBNP, lower body negative pressure; NYHA, New York Heart Association; PRA, plasma renin activity

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